> clerk-install-auth

Install and configure Clerk SDK/CLI authentication. Use when setting up a new Clerk integration, configuring API keys, or initializing Clerk in your project. Trigger with phrases like "install clerk", "setup clerk", "clerk auth", "configure clerk API key", "add clerk to project".

fetch
$curl "https://skillshub.wtf/jeremylongshore/claude-code-plugins-plus-skills/clerk-install-auth?format=md"
SKILL.mdclerk-install-auth

Clerk Install & Auth

Overview

Set up Clerk SDK and configure authentication for Next.js, React, or Express. This skill covers SDK installation, environment variables, ClerkProvider, middleware, and initial auth verification.

Prerequisites

  • Node.js 18+
  • Package manager (npm, pnpm, or yarn)
  • Clerk account at dashboard.clerk.com
  • Publishable Key (pk_test_*) and Secret Key (sk_test_*) from Clerk Dashboard > API Keys

Instructions

Step 1: Install SDK for Your Framework

set -euo pipefail
# Next.js (App Router or Pages Router)
npm install @clerk/nextjs

# React SPA (Vite, CRA, etc.)
npm install @clerk/clerk-react

# Express / Node.js backend
npm install @clerk/express

# Backend-only (Cloudflare Workers, serverless, etc.)
npm install @clerk/backend

Step 2: Configure Environment Variables

# .env.local — never commit this file
NEXT_PUBLIC_CLERK_PUBLISHABLE_KEY=pk_test_...
CLERK_SECRET_KEY=sk_test_...

# Optional: routing URLs
NEXT_PUBLIC_CLERK_SIGN_IN_URL=/sign-in
NEXT_PUBLIC_CLERK_SIGN_UP_URL=/sign-up
NEXT_PUBLIC_CLERK_AFTER_SIGN_IN_URL=/dashboard
NEXT_PUBLIC_CLERK_AFTER_SIGN_UP_URL=/onboarding

Ensure .env.local is in .gitignore:

echo ".env.local" >> .gitignore

Step 3: Add ClerkProvider (Next.js App Router)

// app/layout.tsx
import { ClerkProvider, SignInButton, SignedIn, SignedOut, UserButton } from '@clerk/nextjs'
import './globals.css'

export default function RootLayout({ children }: { children: React.ReactNode }) {
  return (
    <ClerkProvider>
      <html lang="en">
        <body>
          <header className="flex justify-between p-4">
            <SignedOut>
              <SignInButton />
            </SignedOut>
            <SignedIn>
              <UserButton />
            </SignedIn>
          </header>
          {children}
        </body>
      </html>
    </ClerkProvider>
  )
}

Step 4: Add Middleware

// middleware.ts (project root, NOT inside app/ or src/app/)
import { clerkMiddleware, createRouteMatcher } from '@clerk/nextjs/server'

// Define which routes should be publicly accessible
const isPublicRoute = createRouteMatcher([
  '/',
  '/sign-in(.*)',
  '/sign-up(.*)',
  '/api/webhooks(.*)',
])

export default clerkMiddleware(async (auth, req) => {
  if (!isPublicRoute(req)) {
    await auth.protect()
  }
})

export const config = {
  matcher: [
    // Skip Next.js internals and static files
    '/((?!_next|[^?]*\\.(?:html?|css|js(?!on)|jpe?g|webp|png|gif|svg|ttf|woff2?|ico|csv|docx?|xlsx?|zip|webmanifest)).*)',
    // Always run for API routes
    '/(api|trpc)(.*)',
  ],
}

Step 5: Create Sign-In and Sign-Up Pages

// app/sign-in/[[...sign-in]]/page.tsx
import { SignIn } from '@clerk/nextjs'

export default function SignInPage() {
  return (
    <div className="flex min-h-screen items-center justify-center">
      <SignIn />
    </div>
  )
}
// app/sign-up/[[...sign-up]]/page.tsx
import { SignUp } from '@clerk/nextjs'

export default function SignUpPage() {
  return (
    <div className="flex min-h-screen items-center justify-center">
      <SignUp />
    </div>
  )
}

Step 6: Verify Connection

// app/api/health/route.ts
import { auth } from '@clerk/nextjs/server'

export async function GET() {
  const { userId } = await auth()
  return Response.json({
    clerkConnected: true,
    authenticated: !!userId,
    userId: userId || null,
  })
}

React SPA Setup (Vite)

// src/main.tsx
import { ClerkProvider } from '@clerk/clerk-react'
import App from './App'

const PUBLISHABLE_KEY = import.meta.env.VITE_CLERK_PUBLISHABLE_KEY

if (!PUBLISHABLE_KEY) {
  throw new Error('Missing VITE_CLERK_PUBLISHABLE_KEY in .env')
}

ReactDOM.createRoot(document.getElementById('root')!).render(
  <ClerkProvider publishableKey={PUBLISHABLE_KEY}>
    <App />
  </ClerkProvider>
)

Express Setup

// server.ts
import express from 'express'
import { clerkMiddleware, requireAuth, getAuth } from '@clerk/express'

const app = express()

// Apply Clerk middleware globally — attaches auth to all requests
app.use(clerkMiddleware())

// Public route
app.get('/api/health', (req, res) => {
  res.json({ status: 'ok' })
})

// Protected route — redirects unauthenticated requests
app.get('/api/profile', requireAuth(), (req, res) => {
  const { userId } = getAuth(req)
  res.json({ userId })
})

app.listen(3001, () => console.log('Server running on :3001'))

Error Handling

ErrorCauseSolution
Missing publishableKeyEnv var not setAdd NEXT_PUBLIC_CLERK_PUBLISHABLE_KEY to .env.local
ClerkProvider must wrap your applicationHook used outside providerEnsure ClerkProvider wraps root layout
auth() was called but Clerk can't detect clerkMiddleware()Middleware not runningPlace middleware.ts at project root, check matcher
Module not found: @clerk/nextjsPackage not installedRun npm install @clerk/nextjs
500 error on all pagesCLERK_SECRET_KEY missing or wrongVerify key prefix matches environment (sk_test_ for dev)

Enterprise Considerations

  • Use separate Clerk instances per environment (dev/staging/prod)
  • Store keys in platform secrets (Vercel, AWS Secrets Manager), never in .env files committed to git
  • The CLERK_SECRET_KEY must never be exposed client-side; only NEXT_PUBLIC_CLERK_PUBLISHABLE_KEY is safe for browsers
  • For monorepos, install @clerk/nextjs only in the app that needs it; use @clerk/backend for shared server packages
  • Enable Clerk's "Enhanced email deliverability" in production for reliable transactional emails

Resources

Next Steps

Proceed to clerk-hello-world for your first authenticated request.

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┌ repo

jeremylongshore/claude-code-plugins-plus-skills
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